System for repeating or relaying telegraph signals



H. H. HAGLUND ET Al. 1,946,907

SYSTEM FOR REPEATING 0R RELAYING TELEGRAPH SIGNALS Filed Feb. 28, 1931 -2 Sheets-Sheet 1 Feb. 13, I1934.

H. H. HAGLUND Er AL 1,946,907

SYSTE FOR REPETING OR RELYING TELEGRPH SIGNALS l Filed Feb.- 28. 1931 a sheets-snai '2 dtkotmq Patented Feb. 13, 1934 SYSTEM Fon aEPEArING on mimmo TELEGRAPH SIGNALS Hakon H. Haglund, Flushing, and Ronald V. Morgenstern, Irvington, N. Y., assignors to The Western Union Telegraph Company. New York, N. Y., a corporation of New York f Application February 2s, 1931. serial 10.519.206

s claims. (c1. 11s-1o) This invention relates to telegraph systems, and in particular to a repeater or relay system for repeating or relaying telegraph signals.

Our invention relates to a telegraph-repeater jof the type employing a dynamo-electric generator for repeating incoming signals, and an object of our invention is to devise circuits for controlling the energization of the iield windings of said generator in accordance with the signals to be repeated.

More specifically, an object of our invention is to devise a system for controlling the energization of the actuating windings of an electromagnetic repeater, which may be of the dynamo-electric type, in which the circuit arrangements embody relays of the gaseous grid-controlled rectifier tube type. Such rectiiier tubes are characterized by starting into operation upon the application of a certain critical potential applied to the grid, after which the current in the output plate filament circuit continues to flow substantially unaffected by variations in the grid potential. One form of such rectiers has been referred to in various publications as a grid glow-tube. By reason of what may be termed the trigger action of the grid above referred to it was suggested in an article entitled Gas-lled thermionic tubes by A. W. Hull, publishedl in the journal of the American Institute of electrical Engineers, November 1928, that tubes having this characteristic may appropriately be designated by the Greek derivative term thyratron. lowing description and claims we shall for convenience employA this term without restricting it to any particular construction or structure;

-Our invention is illustrated in the accompanying drawings in which:

Figure 1 shows the invention applied to a telegraph set, suitable for simplex working which 40 may be either a one-way repeater or a terminal set. V.

Figures 2 and 3 show duplex terminal sets which may be made part of superposed telegraph systems.

In Figure 1 the two line wires l, 2 are terminated in a shunting network 3 composed of adjustable resistances 4, 5 and adjustableinductances 6, 7. The net work or shunt is tapped at its electrical center 8.

Across each half of shunt 3 is connected the input circuit of a thyratron tube. The grid and filament of thyratron tube 9 are connected respectively to the line and center-tap terminals of that half of the shunt comprising resistance 4 and inductance 6. Similarly the grid and filament of tube 10 of the thyratron type are connected respectively to the line and center-tap terminals of that of the shunt 3 comprising resistance 5 and inductance 7. I

The net work across the line wires and input oo circuit of the thyratron tubes is adjusted in impedance and phase relationship to iit the line .circuit with which it is employed. By so adjusting. this terminating network, the voltage applied to the input circuits of the thyratron tubes o5 can be made substantially free from that signal distortion which is due to theunequal attenuation of signals of different frequencies by the line.

If necessary, stabilizing batteries 1 1 and 12 may be included in therespective input circuits of 7o' the tubes 9 and 10.

The output circuits of the thyratron tubes 9 and 10 are connected together by adjustable condenser 13 and by the resistances 14, 15, 16, 17 in series which shunt it. The purpose of this u linking circuit is to stop the action of one thyratron tube when the other becomes energized, and the values of the condenser and resistances are properly adjusted for this purpose.

The output circuit of thyratron tube 9 extends 80 from filament and battery 18 or other power source through one field winding 19 of a generator 21 and a. network comprising condenser 22 'shunted by suitable resistance 23, thence to the plate or anode of the thyratron tube by Way of resistance 14. The output circuit of thyratron tube 10 extends from iilament and power source 18 through a second iield winding 20 of the same generator, and another similar network comprising condenser 24' shunted'by resistance 25, thence 90 to the anode of thyratron tube 10 by way of resistance 17. I

The-two iield coils 19 and 20 of the generator 21 are connected in opposing relationship to one another so that with equal currents in these coils, o5 there will be vno eld flux and hence no voltage across the armature of the generator, but when only one winding is energized, the armature will supply current of a certain polarity at its terminals, and of opposite polarity when the other 10o winding alone is energized. The armature is connected either 'to terminal apparatus or to the next line section, depending upon whether the set illustrated in Figure 1 is to be used as a. terminal set or as a repeater.

The operation of the circuit of Figure 1 is as follows:

When there are no signals on the line, so lthat neither of the thyratron tubes is started, the currents in the outputcircuits of the thyratron 11| tubes are very small, and, if the thyratron tubes and their associated circuits are matched, as they should be, the currents are equal. Since the two field coils 19 and 20 are connected in opposing relationship to one another, the resultant flux is zero and no voltage is produced in the armature of generator 21.

As signals are received, one or the other of the thyratron tubes, depending upon the polarity of the signals, breaks down and allows current to iiow through the output circuit including the field coil of the generator. Let it be assumed that the incoming 4signal is of such polarity that the voltage drop across 4, 6 tends to make the grid of thyratron tube 9 more positive at the same time the voltage drop across 5, 'l tends to make the grid of thyratron tu-be 10 more negative. The thyratron tube 9 then breaks down and permits a current of substantial magnitude to iiow in the output circuit including the field coil 19 of the generator. Condenser 13 becomes charged by the drop in voltage across resistance 14. The condenser 22 and its shunting resistance 23 in series with field coil k19 serve to give the desired shape to the outgoing current wave from the armature-of the generator. The purpose of thus controlling the v shape of the outgoing current wave is to com pensate for line distortion.

As the polarity of the signal current received from line 1, 2 is reversed, positive potential is applied to the thyratron tube 10 and starts current ow in the output circuit of this tube. At the same time current iiow in the output circuit of tube 9 is stopped by the action of the linking circuit when tube 10 becomes energized. The operation of the linking circuit involves a discharge of condenser 13 through resistances 14, 15, 16 and 1'? and a charging of the condenser in the other direction by the drop in potential across resistance 17. This operation results in reducing the plate voltage of tube 9 below the value necessary to sustain its plate current, and the tubeceases to operate.

The flow of current through field coil 20 in the output circuit of thyratron tube 10, with cessation of current ow in field coil 19, causes a reversal in the direction of the iield flux of output generator 21; hence, a reversal in the voltage across its armature. As before, the condenser 24 and its shunting resistance 25 in series with the field coil 20 serve to give the outgoing current wave from the armature the desired shape.

It is obvious that the arrangement shown could be employed on grounded as well as metallic circuits. By placing the shaping terminal shunt 3 across the arms of a suitable bridge, the arrangement shown could be employed for duplex working when superposed circuits are not utilized.

The circuit shown in Figure 2 is of the type utilizing a bridge composed of four inductances on a common core connected in series with four resistances. This type of bridge is shown in a copending application of R. V. Morgenstern, Serial No. 430,075 led February 20, 1930, entitled Vacuum tube repeaters and terminal sets for superposed telegraph systems. Both the resistances and the inductances may be adjustable if desired but all four arms of the bridge must have the same characteristics or b e. balanced for duplex operation. The input circuit of tube 9 is connected across the arms of the bridge included in line 1, and the input circuit of tube 10 i's connected in an opposite'sense across the arms of the bridge included in line 2. The bridging circuit shown in Figure 1 for automatically stop- I ping one tube when the other becomes energized cannot be used in the circuit shown in Figure 2, but automatic interrupters R1 and Rz are provided in the respective plate circuits of` tubes 9 and 10 for the automatic self-interruption of each plate circuit.

These interrupters function in the following manner: Suppose that a current is flowing in the output circuit of tube 10. If a line signal of the correct polarity to energize tube 9 is now received, current will flow in its output circuit which includes the inductance 28 and the armature or tongue and contact of the automatic interrupter Ri. Inductance 28 is shunted by a circuit which includes condenser 29 and the coil of the automatic interrupter R2, the tongue and contacts of which are placed in the output circuit of tube 10. Current flowing through the inductance 28 in the output circuit of tube 9 will cause a momentary current to flow in the circuit containing the operating c oil of interrupter R2, which in turn will cause the tongue of R2 to leave its contact and momentarily interrupt the output circuit of tube 10, causing it to become energized until a line signal of the proper polarity to again energize it is received, which in a similar manner interrupts the output circuit of tube 9 through the medium of interruptor R1.

The rest of the operation of Figure 2- will be readily apparent from the foregoing description of the operation of Figure 1, it being understood that the ltwo thyratron tubes are connected in opposite senses to the line so that one tube responds to signals of one polarity and the other tube responds to signals of the opposite polarity. The operation of Figure 2 is otherwise the same as Figure 1, except that the plate circuits of the thyratron tubes are interrupted by the selfoperating interrupters Ri and Rz.

The arrangement shown in Figure 3 employs the thyratron tube circuits shown in Figure 1 for operation in connection with a duplex terminal set. In this arrangement the lines 1 and 2 are terminated in a balanced bridge arrangement involving four identical primary windings Pi, P2, Pa and P4, over a transformer having a single secondary winding S. It is understood that the primary windings and the secondary winding are wound upon a common core. The thyratron tubes 9 and 10 are connected in opposed relation between the center-tap of secondary winding S and the outer terminals of this winding, in such manner that the tubes are operated by signals of opposite polarities.

The operation of the circuit arrangement shown in Figure 3 will be apparent from the description of the operation of Figure 1.

We claim:

1. In a signaling system, an input circuit, an output circuit, a repeater element comprising a dynamo having an armature connected to the output circuit and a field winding associated with the input circuit, means including an electrostatically controlled gas discharge tube having an input circuit including a grid element connected to receive the signal impulses and an output circuit including anode and cathode elements connected and arranged to energize said eld winding in accordance with incoming signals, said grid, anode and cathode elements being so constructed and arranged that the output circuit is unaffected by the grid potential after being started 2. In a signaling system, an input circuit, an output circuit, a repeater element comprising a dynamo having an amature connected to the output circuit and a pair of field windings associated with the input circuit, means including an electrostatically controlled gas 'discharge tube having an input circuit including a grid element connectedlto receive the signal impulsesand an output circuit including anode and cathode elements connected and arranged to energize each eld winding from said input circuit in accordance with incoming signals, said grid, anode and cathode elements being so constructed and arranged that the output circuit is unaffected by the grid potential after being started said tubes being connected to said input circuit to respond to signals of opposite polarity.

3. In a signaling system, an input circuit, an output circuit, a repeater element comprising a dynamo having an armature connected to the output circuit, and a pair of field windings, means for energizing one of said field windings in aocordance with signals'of lone polarity received over said input circuit, means for energizing said other winding in accordance with signals of opposite polarity received over said input circuit, said means beingso arranged that said windings are energized in opposite directions and each said means including respectively a thermionic tube relay, said tube being characterized by a starting condition differing from its operating condition, means for applying a signal condition to start said device and means independent of energy supplied by said signal condition for maintaining the discharge.

4. In a signaling system, as set forth'in claim 3, means responsive to the energizationY of one discharge device for deenergizing the other electric discharge device.

5. In a duplex telegraph system, an incoming circuit, an outgoing circuit. a terminal network for balancing said incoming circuit, a repeater element comprising a dynamo having an armature connected to the outgoing circuit, and a pair of' eld windings, means including a relay for energizing one of said field windings in accordance with positive signals received over said input circuit, means including a second relay for energizing said second field winding in opposing relation to said first /field windings in accordance with negative signals received over said input circuit. said relays being of the electrostatically controlled gas dischar'getube type, responsive to short signal impulses. said tube, after a discharge has been started therethrough by a signal impulse, operating irrespective -of signal impulses applied thereto, means responsive to the energization of one relay for deenergizing the other relay, and a signal transmitter connected to said terminal network in conjugate relation to the input circuits of said relays. A

HAKON H. HAGLUND. RONATLD V, MORGENSTERN. 

